Evaporator-condenser unit



P 22, 1964 R. F. PETERSON EVAPORATOR-CONDENSER UNIT 2 Sheets-Sheet 1 i7 /4 4 M I [5 Filed May 1, 1961 United States Patent 3,149,479 EVAPORATOR-CGNDENSER UNIT Ramon F. Peterson, Dowagiac, Mich, assignor to Rudy Manufacturing Company, Dowagiac, Mich a corporation of Michigan Filed May 1, 1961, Ser. No. 186,755 3 Claims. (Cl. 62-474) This invention relates to evaporator and condenser units, and particularly to a unit condenser and evaporator and the method employed in its construction.

In dehumidifiers and like refrigeration devices employing evaporator-condenser units, the construction of both units simultaneously provides a substantial saving in time and therefore cost. In the past, each unit was assembled on its pair of end brackets and the two separate units were connected to each other and the elements of the device when assembled therein. In the present arrangement, both of the coils are assembled simultaneously on the same end brackets. One bracket is placed in the bottom of a fixture over a minimum number of pilot rods which are employed for the purpose of aligning the fins. The proper number of fins for each coil are inserted over the pilot pins for maintaining the remainder of the apertures through the fins in aligned relationship. After the proper number of fins are stacked over the pins in this manner, the second or top bracket is then moved into place over the pins to cover the top fin of the stack. The hairpinshaped length of tubing is then inserted through the remaining apertures of the end brackets and fins. The length of the tubing is such as to have the open ends extend beyond the top bracket so that end caps interconnect tubing of adjacent hairpin portions which form a continuous serpentine tube. The assembly is then removed from the fixture, and the pilot pins and the remaining hairpinshaped length of tube are inserted in the pilot pin openings to complete the coil when the end caps are placed over the opposite ends thereof. It should be apparent that the assembly of the elements to form the two coils on the single pair of end brackets provides a substantial saving in time over that required to construct each coil separately. After the unit is formed in this manner, the bottom branch of the lowermost hairpin of each coil extends through the bracket. The adjacent ends are pinched on opposite sides to produce a small central aperture. The apertures receive the ends of a coiled capillary tube which is sealed in position in series with the two coils. The uppermost leg of the top hairpin of each coil is connected into a refrigeration system. A strainer may be inserted in the leg of the lower hairpin of the condenser portion of the assembly for straining the refrigerant as it flows in the system. After the device is constructed in this manner, it is heated to have all of the joints sweated or soldered, including those of the strainer and the ends of the capillary tube. A more compact unit is made of the evaporator and condenser at a labor cost that would be required for making a single section of the unit. When the capillary tube is applied to both of the units after the independent construction thereof, the actual cost of labor is approximately doubled over that for constructing the two coils interconnected by a capillary tube simultaneously. There is also a saving in space when assembling the two coils in a single unit as there is no working space required between these units. All that is required is to connect the end of each coil to the ends of the tubing of a refrigeration system. It was found that the coil of the'evaporator unit was more eflicient when a less number of fins were employed thereon than on the condenser.

The greatest differential possible is desired between the temperature of the fins of the evaporator and the ambient ICC temperature. It was found for the arrangement herein described that four fins to the inch produced satisfactory evaporation and that proper cooling was produced by the condenser which employed approximately eight fins per inch. It has been understood that these particular fin ratios hold for a particular application and may vary substantially in the number of fins employed by either of the coils. It is desirable to have the edge of the apertures of the fins provided with a tubular extension drawn from the metal at the edge of the apertures, with the ends reversely bent to have a precise over-all length thereto so that a stack of fins will have a predetermined height. The cylindrical extensions prevent electrolysis occurring between the copper tube and the metal of the fin while providing the precise spacing pointed out above.

Accordingly, the main objects of the invention are: to form a dehumidifier unit and the like from separate evaporator and condenser coils built on common end brackets, with the coils interconnected by a capillary coil in series therewith; to form a unit assembly consisting of an evaporator and a condenser coil for a dehumidifier and the like having sinuously formed tubing with separate fins thereover, with the fins of the evaporator substantially half in number of those employed on the condenser portion of the unit; to construct a pair of coils upon common end brackets with fins thereover, with the condenser having substantially twice the number of fins as the evaporator and with the two coils interconnected at the bottom with a capillary coil, with the connection made to the end of each coil at the top to a refrigerant circuit; to construct a unit evaporator and condenser on a common bracket with different numbers of fins thereon spaced apart by tubular extension of the apertures which are of greater length on the tins of the evaporator which employs a lesser number of fins per length of the straight sections of the coil, and, in general, to form a unit evaporator and condenser which is simple in construction and economical of manufacture, with a reduced over-all dimension.

Other objects and features of novelty of the invention will be specifically pointed out or will become apparent, when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a broken view in side elevation of an evaporator and condenser unit embodying features of the invention;

FIG. 2 is an end view of the evaporator illustrated in FIG. 1, as viewed from the point 2 thereof;

FIG. 3 is a top view of the unit evaporator-condenser illustrated in FIG. 1;

FIG. 4 is an end view of the evaporator illustrated in FIG. 1, as viewed from the point 4 thereof;

FIG. 5 is an enlarged, broken sectional view of the structure illustrated in FIG. 1, taken on the line 5-5 thereof, and

FIG. 6 is an enlarged, broken sectional view of the structure illustrated in FIG. 1, taken on the line 6-6 thereof.

Referring to the figures, a pair of end plates 10 and 11 are spaced apart by a plurality of fins 12 in the condenser portion 13 and a plurality of fins 14 in the evaporator portion 15. The coil 16 of the condenser portion and the coil 17 of the evaporator portion are made up of lengths of tube 20 bent in hairpin shape. The hairpin ends extend through apertures in the fins 12 and 14 and are interconnected by caps 18 to form a serpentine-shaped continuous tubular length wihch extends from the top to the bottom of both the evaporator and condenser portions. The end 19 of the condenser coil and the end 21 of the evaporator coil are crimped at 22 to form a central tubular passage of small diameter for receiving the ends of a capillary tube 23 which is provided with turns 24 to form a compact coil.

As more clearly illustrated in FIGS. 3 and 5, the fins 14 of the evaporator portion 15 are spaced farther apart than the fins 12 of the condenser portion 13. In the structure herein illustrated, which is not to be considered limiting, the fins 14 are spaced twice as far apart as the fins 12, being stacked four to the inch, while the fins 12 of the condenser coil are stacked approximately eight to the inch. Apertures 25 through the fins receive the legs 26 of the hairpin-shaped lengths of the tube 20. The legs are enclosed by a tubular wall portion 27 disposed in extension of the aperture 25. The wall portion is drawn from the metal of the aperture at the time it is formed and preferably the outer edge is reversely bent at 28 to have an accurate over-all length so that when a series of the fins are stacked one upon another, a predicted overall length is obtained. The tubular wall portions 27, when sweated to the wall of the legs 26, prevent galvanic action from occurring between the metal of the legs and that of the fins due to the dissimilarity of the metals. The end plates 10 and 11 have cylindrical flanges 29 extending from the apertures therethrough which are also sweated or brazed to the legs 26 extending therethrough. It will be noted from FIG. that the end caps 18 have expanded ends 31 which extend over the ends of the legs 26 in position to be sweated or brazed thereon.

In FIG. 6, the bottom leg 26 of the condenser portion 13 is illustrated as having a strainer 32 mounted therein adjacent to the end thereof. The end is crimped at 22, as pointed out above, to form a small aperture 33 for receiving the end of the capillary tube 23. A single brazing or sweating operation secures the fins and end caps 18 to the legs 26 which are also secured to the end plates and 11, to the capillary coil 23 and to the strainer 32, all in a single heating of the assembled unit.

When assembling the unit, the plate 18 is placed in a fixture over projecting pins which extend through at least two apertures 25 thereof. The fins 12 are assembled on the condenser portion 13 simultaneously with the assembly of the fins 14 on the evaporator portion 15. Thereafter, the plate 11 is placed over the pins against the topmost fins 12 and 14. The legs 26 of the hairpin-shaped tubular elements 28 are inserted through the apertures 25 which do not have the aligning pins therein. The assembly is then removed from the fixture and pins, and addi-' tional hairpin-shaped elements 20 are added to the aperture 25 formerly occupied by the pins. Thereafter, the end caps 18 are applied to the free ends of the legs 26 to complete the coil. The strainer is assembled in the lowermost leg 26 of the condenser, and the end thereof and the end of the adjacent bottom leg 26 of the evaporator are crimped to provide the small apertures 33 for receiving the ends of the capillary tube 23. An elbow 34 is added to the top leg 26 of the condenser. The end 35 of the topmost leg 26 of the evaporator is crimped to reduce its diameter, with its outer end crimped inwardly at the center to form apertures 36 and 37 for different diameter tubes which are to be connected thereto.

After the hairpin tube sections have been assembled within the apertures of the end plates 10 and 11 and the two stacks of fins therebetween, the assembly is moved to a mechanical expander which expands the legs 26 simultaneously in the same time that was required to expand the legs of a single coil. The now rigid assembly goes to a fixture for silver soldering the end caps 18 in place and the ends of the capillary tube in the ends of the lowermost legs 26 of each of the coils. Thebrazing of the capillary tube across the ends of the coil was required of the customer when the condenser and evaporator coils were furnished separately for assembly in a dehumidifier or other refrigerating device. Apertures 38 are provided in the horizontal flanges 39 of the end plates 10 and 11 and apertures 41 and 43 are provided in the vertical flanges 42 of the end plates. The apertures 38, 41 and 43 are used to secure the unit when assembled on a device.

It should be apparent that substantially no more time or labor is required for assembling the two coils on the single pair of end plates for expanding the leg portions of the hairpin tubular elements and for silver soldering the end caps and the capillary tube and strainer in place than was required for assembling any one of the two coils separately. This substantial saving of time is accompanied by the saving in space since the two coils can be placed closer together and assembled in a device as a single unit. The further work of cleaning, testing, dehydrating, capping and packing the two coils as a single part provides a substantial saving also in time and labor over that required when the operations were performed on separate coils. The combination unit is assembled on the dehumidifier chassis or other refrigerating device as one part with no silver soldering required between the coil portions. The inlet and outlet ends are located at the top of the combined unit where they are readily connected into a refrigeration system.

What is claimed is:

1. A unit refrigeration element comprising a single pair of spaced end plates having a row of apertures, a pair of independent sinuous tubular coils supported by said end plates in spaced relation to each other with the row of apertures therebetween, one coil constituting an evaporator, the other coil constituting a condenser, and a tube of smaller diameter than that of said sinuous coils joined in series relation therewith to form a restricted passageway therebetween.

2. A unit refrigeration element comprising a single pair of spaced end plates, a pair of independent sinuous tubular coils supported by said end plates in spaced relation to each other, spaced stacks of spaced fins on said coils, one coil and its associated fins constituting an evaporator, the other coil and its associated fins constituting a condenser, and a tube of smaller diameter than that of said sinuous coils joined in series relation to adjacent ends of said coils to form a restricted passageway therebetween, said tube being in the form of a coil to reduce the overall dimension thereof.

3. A unit refrigeration element comprising a single pair of spaced end plates having a row of apertures, a pair of independent sinuous tubular coils supported by said end plates in spaced relation to each other and to the row of apertures disposed therebetween, one coil having a plurality of fins thereon constituting an evaporator, the other coil having a plurality of fins thereon spaced from the fins on the evaporator constituting a condenser, a tube of smaller diameter than that of said sinuous coils joined in series relation therewith to form a restricted passageway therebetween, and a strainer in the coil constituting said condenser located adjacent to said tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,524,520 Junkers Jan. 27, 1925 1,870,457 Kenney Aug. 9, 1932 2,300,086 Alsing Oct. 27, 1942 2,304,359 Hommel Dec. 8, 1942 2,307,355 Bredeson Ian. 5, 1943 2,354,131 Larkin July 18, 1944 2,669,099 Malkolf Feb. 16, 1954 2,710,509 Ayling June 14, 1955 2,851,571 Pearce Sept. 9, 1958 2,914,842 Modine Dec. 1, 1959 2,932,178 Armstrong Apr. 12, 1960 2,966,781 Schafer et al. Jan. 3, 1961 3,067,592 McFarlan Dec. 11, 1962 

3. A UNIT REFRIGERATION ELEMENT COMPRISING A SINGLE PAIR OF SPACED END PLATES HAVING A ROW OF APERTURES, A PAIR OF INDEPENDENT SINUOUS TUBULAR COILS SUPPORTED BY SAID END PLATES IN SPACED RELATION TO EACH OTHER AND TO THE ROW OF APERTURES DISPOSED THEREBETWEEN, ONE COIL HAVING A PLURALITY OF FINS THEREON CONSTITUTING AN EVAPORATOR, THE OTHER COIL HAVING A PLURALITY OF FINS THEREON SPACED FROM THE FINS ON THE EVAPORATOR CONSTITUTING A CONDENSER, A TUBE OF SMALLER DIAMETER THAN THAT OF SAID SINUOUS COILS JOINED IN SERIES RELATION THEREWITH TO FORM A RESTRICTED PASSAGEWAY THEREBETWEEN, AND A STRAINER IN THE COIL CONSTITUTING SAID CONDENSER LOCATED ADJACENT TO SAID TUBE. 